controlled experiment

基本解释

We can’t know for sure because this is not a controlled experiment.
我们不能确定，因为这不是一个可控实验。
Vicente conducted a randomized, controlled experiment on electoral bribery in São Tomé and Príncipe.
文森特在某非洲小国做了一项关于“贿选”的实验。
History is not a controlled experiment and so we cannot know exactly what would have happened absent a particular Supreme Court decision (or any other event for that matter).
历史是一个不受控制的试验，我们不能确切地知道如果没有最高法院的判决（或其它与之有关的任何事件）将会发生什么。

Researchers adjusted their computer algorithm to the slower insulin absorption rate and on a repeat experiment blood glucose was tightly controlled in all of the subjects.

Indeed, it is why many early medical advances became standard of care without anyone seeing the need for a placebo controlled experiment.
FORBES: When Americans Rejected Small Pox Vaccines
Whatever the mechanism, though, this study provides what no previous study ever has: evidence from a controlled experiment that keystone species really exist.
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